Text-file-encryptor

This project is to encrypt a text file using Caesar cipher method.

Here's the code

import os,shutil dire=os.getcwd() listOfFile=os.listdir(dire) print 'Press Enter to quit' while True: EncryptionValue=int(5) plainFile=raw_input("Enter filename:") if plainFile == "": break if plainFile in listOfFile and plainFile.endswith('.txt'): inputFile=plainFile unEncryptFile='unEncrypted.txt' shutil.copy(plainFile,unEncryptFile) TextFile=open(plainFile,'r') plainText=TextFile.read() cipherText=''

    for ch in plainText:
        ordValue=ord(ch)
        cipherValue=ordValue + EncryptionValue
        if cipherValue > ord('z'):
            cipherValue=ord('a') + EncryptionValue-\
                        (ord("z") - ordValue + 1)
        cipherText += chr(cipherValue)

    TextFile.close()
    TextFile=open(plainFile,'w')
    TextFile.write(str(cipherText))
    TextFile.close()
    newFileName=raw_input("Save unencrypted file as:")
    if newFileName.endswith('.txt') and newFileName not in listOfFile  :
        os.rename(unEncryptFile,newFileName)
        print 'Encryption successful!!!...'

    elif not newFileName.endswith('.txt'):
        print 'Save file as text format.Re-Enter file name.'
    elif newFileName in listOfFile:
        print 'This file name already exists!'
elif plainFile not in listOfFile:
    print "Entry doesn't exist in current working directory."
elif not plainFile.endswith('.txt'):
    print 'Invalid entry.'